Train X starts from point A for point B at the same time that train Y starts from B to A. Point A and B are 300 km apart. The trains are moving at a constant speed at least at 25 km/h. The trains meet each other 3 hours after they start. If the faster train takes at least 2 more hours to reach the destination, by which time will the slower train have definitely reached its destination? (ignoring the length of trains in crossing)
Train X starts from point A for point B at the same time that train Y starts from B to A. Point A and B are 300 km apart. The trains are moving at a constant speed at least at 25 km/h. The trains meet each other 3 hours after they start. If the faster train takes at least 2 more hours to reach the destination, by which time will the slower train have definitely reached its destination? (ignoring the length of trains in crossing)
The correct option is B 7.5 hours after the start
Let the speed of X and Y be the x km/h and y km/h respectively. Since they meet after 3 hours, so, x + y = 100. Since the faster train takes at least 3 + 2 = 5 hours to complete the 300 km journey. Hence, minimum possible speed for the slower train = 40 km/h at which speed it will take 7.5 h to complete the journey (7.5=30040)
7.5 hours after the start
Let the speed of X and Y be the x km/h and y km/h respectively. Since they meet after 3 hours, so, x + y = 100. Since the faster train takes at least 3 + 2 = 5 hours to complete the 300 km journey. Hence, minimum possible speed for the slower train = 40 km/h at which speed it will take 7.5 h to complete the journey (7.5=30040)
